The development of human society has lasted for thousands of years during which it has accumulated brilliant human civilization. In the development of human civilization, the communication between persons is the necessary condition and medium for the emergence and development of civilization. With the rapid development of science and technology, the way of communication between persons has been passed from the beginning of oral communication to the transmission of information through paper and other materials, and to the communication of sending messages using telegraph machines. The communication such as the telephone and mobile communication has greatly accelerated the development of human civilization.
With the advancement and development of communication technology, a variety of communication technologies and communication means are emerging. In addition to the purpose of transmitting information better and faster, its main purpose is to provide safe and reliable information exchange and information interaction. In particular, the radio communication and optical communication technologies, which use different frequencies to carry different information to achieve the interaction of a large amount of information, has rapid development. It is desired that the security of information transmission can be ensured while a large amount of information is transferred quickly. Therefore, ensuring information security has become the theme of the times. Over time, communication security technologies based on radio communications and optical communications are changing rapidly.
Secure communication means currently used can basically be divided into two categories: one is to encrypt a carrier frequency, i.e. using the so-called “frequency hopping”: that is, within a certain spectrum range, carrier communication is not carried out using a fixed radio frequency or optical frequency, but is carried out alternately using different frequencies according to a pre-planned law of frequency variation. This makes it impossible for the third party to grasp the actual communication frequency, thus achieving more secure communication. Furthermore, this kind of security technology has been invented by Heidi Rama for nearly 80 years, and the technology is quite mature. In addition to encryption, it can also play a good anti-interference effect to a certain extent. Moreover, if the frequency hopping rate is higher (such as hopping thousands of times per second, that is, the dwell time at each frequency point is in milliseconds), the more complicated the “frequency hopping pattern” is, the more secure the communication is. Because of these characteristics, it is widely used in aspects of military communications and electronic countermeasures etc. Another way of secure communication is to perform encryption processing on a digital baseband portion, i.e., implement secure communication by using complex digital coding of the original information. In practical applications, in order to make communication more secure, in many cases, frequency hopping and encoding are used simultaneously, thereby increasing the difficulty of cracking to improve confidentiality and security. However, regardless of which existing secure communication method (such as conventional frequency hopping and adaptive frequency hopping of frequency hopping technology, digital cryptography, etc.) is used, the channel bandwidth occupied by the communication channel is fixed. In this way, even if the security means of the frequency hopping plus baseband digital coding is used, the frequency hopping spectrum of a certain fixed channel width can be received and acquired by a spectrum analyzer. According to the obtained frequency hopping spectrum, the transmitted encoded signal can be obtained, and can be then repeatedly cracked by a mainframe computer using various decryption algorithms. It is possible to crack the used codes for obtaining the transferred information.
The core of the present disclosure is to implement secure communication by using a modified channel circuit to make the communication channel width dynamically agile on the basis of the foregoing two. It is completely different from the existing principle of secure communication and is a new principle of secure communication.
Since there is currently no instrument similar to the spectrum scanning and monitoring spectrum to scan the monitoring channel width agility, the present disclosure provides another basic secure communication means.